A liquid processing process is one of several processes of manufacturing a semiconductor device, in which a substrate such as, for example, a semiconductor wafer (hereinafter, simply referred to as a “wafer”) is rotated around a vertical axis, and a processing liquid is supplied to the rotating substrate. The processing liquid scattered from the substrate by a centrifugal force is received and collected by a cup that surrounds the circumference of the substrate. When the bottom surface or the periphery of the substrate is processed, the process is performed in a state where the top surface of the substrate is covered with a top plate (also referred to as an upper plate or a cover member) in order to suppress the processing liquid scattered from the substrate from being attached on the top surface of the substrate. When the process is repeated, deposits which are formed from dried and solidified processing liquids or reaction products are gradually deposited on the cup or the top plate. Since a release of such deposits causes particles, members around the substrate, such as the cup, and the top plate are regularly cleaned.
Japanese Patent Laid-Open Publication No. 2000-315671 discloses a cleaning substrate (cleaning jig) configured to clean a cup. A plurality of inclined surfaces of which height is increased toward the periphery of a substrate are intermittently disposed in a circumferential direction on the peripheral portion of the top surface of the cleaning substrate. When the cleaning substrate is rotated by being held by a spin chuck, and a cleaning liquid is supplied to the central portion of the top surface of the cleaning substrate, the cleaning liquid is diffused outward by a centrifugal force. Here, the cleaning liquid that passes along the inclined surfaces is scattered toward a higher position of the cup, and the cleaning liquid that does not pass along the inclined surfaces is scattered toward a lower position of the cup. By this, several height positions of the cup may be cleaned.
However, in a substrate processing apparatus which is configured to process a wafer by supplying a processing liquid to the bottom surface of the wafer but is not provided with a nozzle configured to supply a processing liquid or a cleaning liquid to the top surface of the wafer, even through the cleaning substrate as described above is used, a cup portion higher than the bottom surface of the cleaning substrate cannot be cleaned. In such a substrate processing apparatus, in order to clean a position higher than the bottom surface of the cleaning substrate by using the cleaning substrate, it is contemplated to provide a dedicated cleaning liquid nozzle configured to supply a cleaning liquid to the top surface of the wafer, but this results in an increase of a device cost.